header{
    display: block;
    margin: 0 auto;
    width: 100%;
    text-align: center;
}
header h1{
    font-family: Arial;
    font-size: 40px;
    font-weight: bold;
}
header #newgamebtn{
    width: 100px;
    padding: 10px;
    display: block;
    margin: 20px auto;
    text-decoration: none;
    background-color: #8f7a66;
    font-family: Arial;
    color: white;
    border-radius: 10px;
}
header #newgamebtn:hover{
    background-color: #9f8b77;
}
header p{
    font-size: 30px;
    margin:20px auto;
    
}
/* 整体500px 小格子100px r6px #ccc0b3  格子和四周的间距20px*/
/* 区域 w h 460 p 20  bgc#bbada0 上下50px 居中*/
#grid-container{
    width: 460px;
    height: 460px;
    padding: 20px;
    background-color: #bbada0;
    margin: 50px auto;
    border-radius: 10px;
    position: relative;
}
.grid-cell{
    width: 100px;
    height: 100px;
    border-radius: 6px;
    background-color: #ccc0b3;

    position: absolute;
}
.number-cell{
    border-radius: 6px;

    font-family: Arial;
    font-weight: bold;
    font-size: 60px;
    line-height: 100px;
    text-align: center;

    position: absolute;
}